Royal Wedding 2011: Top 8 Moments of William and Catherine's Big Day

There was so much to love today as Prince William and Catherine Middleton were married in Westminster Abbey as an audience of hundreds of millions worldwide looked on.

There were the hats. The much-anticipated wedding dress. The fairy-tale story of two college roommates going from friends to lifetime mates, a commoner meeting her Prince Charming. There were the glances of adoration between William and Middleton during the ceremony. And then there was Prince Harry.

The World Watches and Tweets

There were 2.6 million Tweets regarding the royal wedding today. Many people attended Royal Wedding parties, sipping tea and champagne and eating scones. Crowds waved Union Jack flags and some people even dressed as brides and kings.

A girl from London, part of group whose cheeks were painted with images of William and Kate, said, "We could feel Diana's spirit."

The wedding was watched by more than 2 billion people worldwide and crowds of at least 600,000 lined the streets to watch the wedding on Jumbotrons

The Crazy Hats

The hats seemed to be on everyone's lips -- and Tweets -- as the wedding guests arrived to Westminster Abbey.

There were the simple and elegant -- Queen Elizabeth II's marigold hat adorned with silk roses -- and the downright horrid -- Princesses Beatrice's and Eugenie's mix of feathers and bows.

Taking the Vows and Exchanging of Rings

Flanked by Middleton's father and William's brother, Harry, the two said their vows while holding hands and looking into each other's eyes. Middleton opted for a modernized version for her vows, dropping the word "obey" and choosing "to comfort."

When William placed the ring made of Welsh gold on Middleton's finger, it seemed a bit tight and he struggled to slip it on.

Kate Middleton's Dress

It was the year's most anticipated outfit and Middleton delivered. And as she stepped out of the 1950s Rolls-Royce loaned to her by the queen, all eyes were fixed on her gown.

Middleton's dress was a lace and ivory satin design by Sarah Burton, the creative director for the late Alexander McQueen. Middleton paired the dress with a "halo" tiara made by Cartier and loaned to her by the queen, and a simple bouquet.

Many said it was reminiscent of Grace Kelly's dress. Kelly, a commoner, married into royalty when she wed Prince Rainier of Monaco.

Pippa Middleton

Middleton's maid of honor, sister Pippa Middleton, was by her side at all times, picking up and carrying the train and at times even the bouquet.

She was dressed in a gown of ivory-colored satin-based crepe also made by Burton. Pippa Middleton led the young bridal party into the abbey, holding the hands of the youngest bridesmaids.

From the Mouths of Royals

As Middleton made her way down the aisle, Prince William faced forward toward the altar but his younger brother, Prince Harry, could not resist. Cameras captured him looking back and then appearing to whisper to his brother: "She is here now."

Michael Middleton, the bride's father, smiled as he accompanied his daughter out of the car. After they entered the Abbey, he turned to Catherine and asked: "Are you ready? You look great."

When Middleton joined William at the altar for the ceremony, he told her: "You look beautiful." And after the wedding, as the two got into the carriage as man and wife, it was reported that he said to her: "I am so happy."

The Kiss

It was the kiss seen around the world ... twice. The two stepped out onto the balcony of Buckingham Palace and waved at the crowds below. With the bridal party, the royal family and the bride's family behind and alongside them, Middleton and William kissed quickly.

The crowd cheered and started chanting "Kiss her again" and William obliged, planting a much longer smooch on his new wife, the duchess of Cambridge.

The Car Ride

The couple left Buckingham Palace and headed to Clarence House in a vintage open-top Aston Martin -- with Prince William at the wheel.

ABC News staff contributed to this story.

Watch a special 2-hour edition of "20/20" at 9 p.m. ET tonight to look at the big day, the night-time celebrations, and what's next for the happy couple, with Barbara Walters.